import java.util.Scanner;

/**
 * Created by forcht on 2018/4/23.
 */
public class Main {

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        double n;
        int m;
        while (scanner.hasNextInt()){
            n=scanner.nextInt();
            m=scanner.nextInt();
            double sum=0;
            for(int i=0;i<m;i++){
                sum+=n;
                n=Math.sqrt(n);
            }
            System.out.printf("%.2f",sum);
        }
    }
}
